Geometry Deviations Research Articles

Автоматизация визуального контроля фотошаблонов для изделий микроэлектроники

The choice of a specific research topic was caused by a request for the development and implementation of automatic optical inspection at a semiconductor plant. The purpose of the work was to develop requirements, conduct technical design and create an optical control system for geometry deviations from a photomask drawing and a conductive pattern obtained using a manual stencil printer using relatively inexpensive equipment. As a result of the research, a pilot design sample of an automated optical control system using relatively inexpensive equipment was created and a computational algorithm was developed that ensures increased performance of the visual image recognition system, which allows to significantly reduce the percentage of defects. The work describes the implemented algorithm for obtaining images by an optical system and extracting images from a drawing file. Regardless of the method of obtaining an image (optical system, scanning electron microscope), there remains interest in choosing a criterion for comparing the obtained image with the reference one. The paper studies quantitative empirical metrics - Mean Square Error and Peak Signal-to-Noise Ratio for various noise reduction methods Block-Matching and 3D filtering and the classical spatial filtering method of Gaussian blur. The sensitivity of the structural similarity index metric to structural distortions of images after noise reduction is checked, taking into account the minimum values of the structural elements of metal-ceramic housings. Based on the Rosner test applied to the obtained values of the structural similarity metric, images containing defects are identified. The user interface provides for the output of the image area with a defect to the operator's screen.

Remote Inspection of Bridges with the Integration of Scanning Total Station and Unmanned Aerial Vehicle Data

Remote visual inspections are valuable tools for maintaining bridges in safe operation. In the case of old structures with incomplete documentation, the verification of dimensions is also an essential aspect. This paper presents an attempt to use a Scanning Total Station (STS) and Unmanned Aerial Vehicle (UAV) for the inspection and inventory of bridge dimensions. The STS’s measurements are conducted by applying two methods: the direct method using a total station (TS) and advanced geometric analyses of the collected point cloud. The UAV’s measurements use a Structure from Motion (SfM) method. Verification tests were conducted on a steel truss railway bridge over the largest river in Poland. The measurements concerned both the basic dimensions of the bridge and the details of a selected truss connection. The STS identified a significant deviation in the actual geometry of the measured connection and the design documentation. The UAV’s inspection confirmed these findings. The integration of STS and UAV technologies has demonstrated significant advantages, including STS’s high accuracy in direct measurements, with deviations within acceptable engineering tolerances (below a few mm), and the UAV’s efficiency in covering large areas, achieving over 90% compliance with reference dimensions. This combined approach not only reduces operating costs and enhances safety by minimizing the need for heavy machinery or scaffolding but also provides a more comprehensive understanding of the structural condition.

Current Collection Quality of High-Speed Rail Pantograph-Catenary Considering Geometry Deviation at 400 km/h and Above

Current Collection Quality of High-Speed Rail Pantograph-Catenary Considering Geometry Deviation at 400 km/h and Above

Asymptotic bound on slow-roll parameter in stringy quintessence model

We study the late time behavior of the scalar part of the volume modulus and the dilaton in stringy quintessence model, focusing on their contributions to the Hubble slow-roll parameter ϵ which directly measures the deviation of the spacetime geometry from de Sitter space. When only one of the moduli is allowed to move, ϵ converges to the stable fixed point at late time. The fixed point value is larger than 1, thus the slow-roll cannot be realized. Moreover, if the decay rate of the quintessence potential is larger than some critical value, the positivity of the potential imposes that the stable fixed point value is just given by 3, independent of the details of the moduli dynamics. Otherwise, the fixed point value coincides with the potential slow-roll parameter. When both the volume modulus and the dilaton roll down the potential simultaneously, we can find the relation between the contributions of two moduli to ϵ satisfied at the fixed point. In this case, the fixed point value is not in general the simple sum of fixed point values in the single field case and cannot be larger than 3.

Synchrotron X-ray imaging of the formation of geometry deviations during percussion laser drilling with ultrashort pulses

Synchrotron X-ray imaging of the formation of geometry deviations during percussion laser drilling with ultrashort pulses

Real-time Physically Guided Hair Interpolation

Strand-based hair simulations have recently become increasingly popular for a range of real-time applications. However, accurately simulating the full number of hair strands remains challenging. A commonly employed technique involves simulating a subset of guide hairs to capture the overall behavior of the hairstyle. Details are then enriched by interpolation using linear skinning. Hair interpolation enables fast real-time simulations but frequently leads to various artifacts during runtime. As the skinning weights are often pre-computed, substantial variations between the initial and deformed shapes of the hair can cause severe deviations in fine hair geometry. Straight hairs may become kinked, and curly hairs may become zigzags. This work introduces a novel physical-driven hair interpolation scheme that utilizes existing simulated guide hair data. Instead of directly operating on positions, we interpolate the internal forces from the guide hairs before efficiently reconstructing the rendered hairs based on their material model. We formulate our problem as a constraint satisfaction problem for which we present an efficient solution. Further practical considerations are addressed using regularization terms that regulate penetration avoidance and drift correction. We have tested various hairstyles to illustrate that our approach can generate visually plausible rendered hairs with only a few guide hairs and minimal computational overhead, amounting to only about 20% of conventional linear hair interpolation. This efficiency underscores the practical viability of our method for real-time applications.

Mechanical properties of additively manufactured lattice structures composed of zirconia and hydroxyapatite ceramics

Ceramic lattices hold great potential for bone scaffolds to facilitate bone regeneration and integration of native tissue with medical implants. While there have been several studies on additive manufacturing of ceramics and their osseointegrative and osteoconductive properties, there is a lack of a comprehensive examination of their mechanical behavior. Therefore, the aim of this study was to assess the mechanical properties of different additively manufactured ceramic lattice structures under different loading conditions and their overall ability to mimic bone tissue properties.Eleven different lattice structures were designed and manufactured with a porosity of 80% using two materials, hydroxyapatite (HAp) and zirconium dioxide (ZrO2). Six cell-based lattices with cubic and hexagonal base, as well as five Voronoi-based lattices were considered in this study. The samples were manufactured using lithography-based ceramic additive manufacturing and post-processed thermally prior to mechanical testing. Cell-based lattices with cubic and hexagonal base, as well as Voronoi-based lattices were considered in this study. The lattices were tested under four loading conditions: compression, four-point bending, shear and tension.The manufacturing process of the different ceramics leads to different deviations of the lattice geometry, hence, the elastic properties of one structure cannot be directly inferred from one material to another. ZrO2 lattices prove to be stiffer than HAp lattices of the same designed structure. The Young’s modulus for compression of ZrO2 lattices ranges from 2 to 30GPa depending on the used lattice design and for HAp 200MPa to 3.8GPa. The expected stability, the load where 63.2% of the samples are expected to be destroyed, of the lattices ranges from 81 to 553MPa and for HAp 6 to 42MPa.For the first time, a comprehensive overview of the mechanical properties of various additively manufactured ceramic lattice structures is provided. This is intended to serve as a reference for designers who would like to expand the design capabilities of ceramic implants that will lead to an advancement in their performance and ability to mimic human bone tissue.

An adjustable acoustic metamaterial cell using a magnetic membrane for tunable resonance

Acoustic metamaterials are growing in popularity for sound applications including noise control. Despite this, there remain significant challenges associated with the fabrication of these materials for the sub-100 Hz regime, because acoustic metamaterials for such frequencies typically require sub-mm scale features to control sound waves. Advances in additive manufacturing technologies have provided practical methods for rapid fabrication of acoustic metamaterials. However, there is a relatively high sensitivity of their resonant characteristics to sub-mm deviations in geometry, pushing the limits of additive manufacturing. One way of overcoming this is via active control of device resonance. Here, an acoustic metamaterial cell with adjustable resonance is demonstrated for the sub-100 Hz regime. A functionally superparamagnetic membrane—devised to facilitate the fabrication process by eliminating magnetic poling requirements—is engineered using stereolithography, and its mechanical and acoustic properties are experimentally measured using laser Doppler vibrometry and electret microphone testing, with a mathematical model developed to predict the cell response. It is demonstrated that an adjustable magnetic acoustic metamaterial can be fabricated at ultra-subwavelength dimensions (≤λ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\le \\lambda$$\\end{document}/77.5), exhibiting adjustable resonance from 88.73 to 86.63 Hz. It is anticipated that this research will drive new innovations in adjustable metamaterials, including wider frequency ranges.

Influence of geometric imperfections of flange joints on the fatigue load of preloaded bolts

In an ideal flange joint configuration, the fatigue endurance of preloaded bolts is contingent upon factors such as the magnitude of preload, applied working load, and the geometric dimensions of the flange. However, real-world flanged joints often deviate from this ideal geometry, introducing imperfections that can markedly escalate the fatigue burden on bolts. This study endeavors to simulate the geometric imperfections inherent in a standard DN40 flange and ascertain their impact on bolt fatigue through a combination of empirical measurements and finite element (FE) analysis. The investigation reveals that even minor deviations in flange geometry, such as non-parallelism on the order of 0.03 mm, can exert a considerable influence on bolt fatigue, particularly when the flange gap aligns with the applied eccentric working load (same side). To mitigate the deleterious effects of these imperfections, the proposal and evaluation of employing filler material between the flanges are made. Specifically, it is demonstrated that a thin layer of liquid metal filler (KemisKit Fe21), substantially alleviates the fatigue burden on bolts. Empirical findings illustrate that this corrective measure enhances the fatigue life of bolts by a factor of more than 30 under the highest applied working load condition.

Tibiofemoral bone configuration is not associated with hamstring muscle strength in male and female patients with ACL reconstruction.

Previous evidence indicated that the tibiofemoral bone configuration might elevate the risk of an anterior cruciate ligament (ACL) injury. Furthermore, a low hamstring-to-quadriceps muscle ratio predisposes especially females to unfavourable knee kinematics. The primary objective of the present study was to investigate sex-specific associations between tibiofemoral bone geometry and isokinetic knee flexion torque in patients with primary ACL injury followed by ACL reconstruction. N = 100 patients (72 = male, 28 = female, age = 31.3 ± 10.2, body mass index = 25.3 ± 3.6) with primary ACL rupture with isokinetic knee flexion torque assessments before and 6 months after ACL reconstruction surgery were analysed. Magnetic resonance imaging scans were analysed for medial posterior tibial slope (MPTS) and lateral posterior tibial slope, notch width index (NWI) and lateral femoral condyle index (LFCI). Additionally, isokinetic knee flexion torque (60°/s) and hamstring-quadriceps ratios were evaluated. Subsequently, functional parameters were correlated with imaging data for gender subgroups. The findings showed that presurgical isokinetic knee flexion torque was not associated with any marker of femoral or tibial bone geometry. Further, while significant differences were observed between female (0.883 ± 0.31 Nm/kg) and male (1.18 ± 0.35 Nm/kg) patients regarding preoperative normalized knee flexion torque (p < 0.001), no significant sex differences were found for percentage increases in normalized knee flexion torque from presurgery to postsurgery. Generally, female patients demonstrated significantly higher MPTS magnitudes (p < 0.05) and lower LFCI values (p < 0.05) compared to men. The present results demonstrated no association between tibial or femoral bone geometry and muscle strength of the hamstrings in patients with ACL reconstruction, indicating an important mismatch of muscular compensation to deviations in bone geometry. There were no sex-specific differences in tibiofemoral bone parameters. Level III.

Testing beyond-Kerr spacetimes with GWTC-3

The Kerr spacetime is a fundamental solution of general relativity (GR), describing the gravitational field around a rotating, uncharged black hole (BH). Kerr spacetime has been crucial in modern astrophysics and it serves as a foundation for the study of gravitational waves (GWs). Possible deviations in Kerr geometry may indicate deviations from GR predictions. In this work, we consider the Johannsen–Psaltis metric, which is a beyond-Kerr metric characterized by a single free parameter, and then we probe this theory framework using several GWs observations from the third Gravitational-wave Transient Catalog (GWTC-3). We find that, for most of the events analyzed, there are no significant deviations from the null hypothesis, i.e. the Kerr metric. Our main findings demonstrate alignment and certain enhancements when compared to previous estimates documented in the literature.

(114) Mathematical Model for Peyronie's Disease

Abstract Introduction Peyronie's disease may affect up to 20% of men worldwide. After the curvature, penile length loss is the most common complaint. The severity of the curve angle is associated to with penile length and volume loss. Objective Create a theoretical mathematical formula to help clinicians and patients to estimate the penile length and volume loss in patients with Peyronie's Disease. Methods Applying Euclidean Trigonometric principles an geometric axioms a mathematical formula was created. Inserting measurements that are commonly retrieved from patients with Peyronie's disease, i.e., Penile girth, length, and curvature angle in the formula, a 2-d dimensional triangle is created. Applying the torus equation the arc length and angular deviation is found and the the penis volume and lenght loss can be calculated. Results A mathematical formula to evaluate the penile volume and length loss was created accounting for the deviations in the penile geometry occuring in patients with monoplanar and multiplanar Peyronie’s disease deviations. Conclusions This formula provides a mathematically accurate method to predict potential loss of penile length and volume in patients with monoplane or multiplanar Peyronie's disease. The model can be an additional tool for advising patients between shortening or lengthening procedures and help physicians and patients set expectations for results after surgical procedures. Disclosure No.

Prediction of fatigue life of geometrically deviated steam turbine blades under thermo-mechanical conditions

This study explores the intricate factors affecting the fatigue life of steam turbine blades, encompassing steam flow-induced bending, centrifugal loading, vibration response, structural mistuning, and temperature-dependent influences. By focusing on the significance of mistuned steam turbine blades with varying blade geometries due to manufacturing tolerances, this research has paramount relevance for the power generation industries. By employing finite element analysis (FEA) software, a simplified, mistuned, scaled-down steam turbine bladed disk model was developed, considering temperature-dependent material properties. Initial FEA provided insights into the vibration characteristics and steady-state stress responses, with numerical stress distributions evaluated, which were subsequently exported to Fe-Safe software for fatigue life calculations based on centrifugal and harmonic sinusoidal pressure loadings. By investigating the vibration characteristics and response to geometric blade variations, this study affirmed the reliability of the developed FEA model, with findings highlighting the pronounced sensitivity of fatigue life to blade length, width, and thickness variations, in this order. However, in order to validate the developed numerical models, analytical life cycle assessments were calculated, which exhibited a discrepancy of under 3.37%, reinforcing the applicability of the developed numerical methodology to real-world scenarios involving mistuned steam turbine blades experiencing manufacturing deviations in blade geometry.

Exciton interactions of chlorophyll tetramer in water-soluble chlorophyll-binding protein BoWSCP

The exciton interaction of four chlorophyll a (Chl a) molecules in a symmetrical tetrameric complex of the water-soluble chlorophyll-binding protein BoWSCP was analyzed in the pH range of 3–11. Exciton splitting ΔE = 232 ± 2 cm−1 of the Qy band of Chl a into two subcomponents with relative intensities of 78.1 ± 0.7 % and 21.9 ± 0.7 % was determined by a joint decomposition of the absorption and circular dichroism spectra into Gaussian functions. The exciton coupling parameters were calculated based on the BoWSCP atomic structure in three approximations: the point dipole model, the distributed atomic monopoles, and direct ab initio calculations in the TDDFT/PCM approximation. The Coulomb interactions of monomers were calculated within the continuum model using three values of optical permittivity. The models based on the properties of free Chl a in solution suffer from significant errors both in estimating the absolute value of the exciton interaction and in the relative intensity of exciton transitions. Calculations within the TDDFT/PCM approximation reproduce the experimentally determined parameters of the exciton splitting and the relative intensities of the exciton bands. The following factors of pigment-protein and pigment–pigment interactions were examined: deviation of the macrocycle geometry from the planar conformation of free Chl; the formation of hydrogen bonds between the macrocycle and water molecules; the overlap of wave functions of monomers at close distances. The most significant factor is the geometrical deformation of the porphyrin macrocycle, which leads to an increase in the dipole moment of Chl monomer from 5.5 to 6.9 D and to a rotation of the dipole moment by 15° towards the cyclopentane ring. The contributions of resonant charge-transfer states to the wave functions of the Chl dimer were determined and the transition dipole moments of the symmetric and antisymmetric charge-transfer states were estimated.

Fixture Layout Optimization for Remanufacturing Using Directed Energy Deposition Process

Remanufacturing of aero-engine blade components is vital for sustainability and cost-efficiency in aerospace and energy industries. These types of products are sometimes damaged during use but may be successfully repaired using additive manufacturing processes, e.g., Directed Energy Deposition (DED). During this process, precise and reliable fixturing during machining and repairs is crucial as it impacts the final geometric outcome of the remanufactured component. In this study, the fixture layout during the DED process for optimal geometric outcome is considered. Initially, the placement zones in the part surfaces are defined, and the problem space is discretized. A greedy optimization algorithm is considered for the optimization of the clamping positions to achieve the highest geometric quality. The surface on which the material is deposited is measured and analyzed. The optimal fixture layout to achieve minimum deviation on this surface prior to the DED process is identified. The DED process is then simulated, and the deviation in the final geometry is analyzed before and after optimization. Accurate simulation of the DED process using the inherent strain approach allows for verification of the optimization of the fixture layout. The result of this study shows the importance of locating and clamping placement for the remanufacturing process using the DED process.

GPS&V Textual Language

The ISO Technical Committee 213 (TC 213) develops standards about geometrical product specifications and verification (GPS&V). Those standards define both the meaning (semantic) and the writing (syntax) of specification indications used in Technical Product Documentation to control the size, geometry and surface texture deviation allowance on a mechanical part. The specification indications are defined as graphical symbols whose dimension and proportion are described in different ISO standards. The arrangement of those symbols is standardized so that reliable if not univocal information can be conveyed from the writer of the specification indication to the readers of the specification indication. This set of standardized rules constitutes a Graphical Language, primarily developed for humans widely used on two dimensional drawings or in three dimensional models. However, since the specifications are becoming more and more complex it is foreseen that the machines will be more involved in the communication process of the geometrical tolerancing information in the future. This paper describes in some details a context-free grammar that has been written to test the feasibility of a machine-readable Textual Language development.The grammar is based on the Universal Coded Character set (UCS). It shall be able to convey the same information as the current Graphical Language defined in ISO standards. The paper also reports on some testing tools that have been developed and made publicly available through a web interface. While this paper is only concerned with the syntax of the specification indications, some proposals are presented for an extended use of the grammar to check also semantic rules.

Local Thickness Optimization of Functionally Graded Lattice Structures in Compression

This paper presents a new method for optimizing the thickness distribution of a functionally graded lattice structure. It links the thickness of discrete lattice regions via mathematical functions, reducing the required number of optimization variables while being applicable to highly nonlinear models and arbitrary optimization goals. This study demonstrates the method’s functionality by altering the local thickness of a lattice structure in compression, optimizing the structure’s specific energy absorption at constant weight. The simulation results suggest significant improvement potential for the investigated Simple Cubic lattice, but less so for the Isotruss variant. The energy absorption levels of the physical test results closely agree with the simulations; however, great care must be taken to accurately capture material and geometry deviations stemming from the manufacturing process. The proposed method can be applied to other lattice structures or goals and could be useful in a wide range of applications where the optimization of lightweight and high-performance structures is required.

Effect of Grain Size and Layer Thickness on Hardened State Properties in Selective Cement Activation

AbstractThis article demonstrates the effect of varying the maximum grain size and the layer thickness of the particle bed on hardened state properties in Selective Cement Activation (SCA). The compressive strength and geometry (deviation from nominal geometry, surface roughness) are analyzed. Supplementary investigations (μCT, μRFA) are performed to explain the causes of the observed effects. It is found that the compressive strength of the manufactured specimens increases with decreasing layer thickness. This is attributed to reduced process‐induced segregation of the particle bed and fewer process‐induced voids. The geometric precision as well as the surface roughness of the printed test specimens do not differ significantly. As the grain size increases, the amount of compaction required to achieve the target packing density decreases. The compressive strength was found to increase when the grain size in the specimen is reduced. As the finer particle mixtures tend to have less void formation as a result of water application, an increased density of the specimen can be observed. The lower porosity as well as the smaller pores also have a favorable effect on geometric precision, which tends to increase with reduced grain size. At the same time, a lower surface roughness is also present.

Pentacoordinate Mixed-Ligand Zn(II) Complexes with Flufenamato and Niflumato Ligands: Crystal Structure, Spectral Characterization and Biological Properties

Mixed-ligand complexes featuring a carboxylato ligand and bidentate chelate N,N′-donor ligands along with a single halogenido ligand are rarely subjected to studies despite their interesting physical, chemical and biological properties. A direct synthesis involving non-steroidal anti-inflammatory drugs flufenamic acid and niflumic acid and sterically hindering N,N′-donor ligands (neocuproine and 2,2′-biquinoline) has been used to prepare mononuclear mixed-ligand zinc complexes with a composition of [ZnCl(flu)(neo)] (1A and 1B) and [ZnCl(nif)(biq)] (2). Single-crystal X-ray diffraction data have shown that the carboxylate binding mode differs in the two polymorphs 1A and 1B, which form molecules of same composition, and the deviations in molecular geometry are further reflected in their supramolecular structures. The inter- and intramolecular interactions and their contributions to the stability of the crystal structures has been investigated by Hirshfeld surface analysis. The spectral properties of the prepared complexes in solid-state and solution have been analyzed. Additionally, the interaction with the biomacromolecules (fish sperm DNA, human and bovine serum albumins), studied by fluorescence assays, showed a stronger binding of 1A and 1B in comparison with 2.

Fatigue life prediction of mistuned steam turbine blades subjected to deviations in blade geometry

The blades of the steam turbine are subjected to bending of the steam flow, centrifugal loading, vibration response, and structural mistuning. These factors mentioned contribute significantly to the fatigue failure of steam turbine blades. Low pressure (LP) steam turbines experience premature blade and disk failures due to the stress concentrations in the root location of the blade of its bladed disk. This study of mistuned steam turbine blades subjected to variation in blade geometry will be of great significance to the electricity generation industry. A simplified, mistuned, scaled-down steam turbine bladed disk model was developed using ABAQUS finite element analysis (FEA) software. The acquisition of the vibration characteristics and steady-state stress response of the disk models was carried out through FEA. Such studies are very limited. Subsequently, numerical stress distributions were acquired and the model was subsequently exported to Fe-Safe software for fatigue life calculations based on centrifugal and harmonic sinusoidal pressure loading. Vibration characteristics and response of the variation of the geometric blade of the steam turbine were investigated. Natural FEA frequencies compared well with the published literature of real steam turbines, indicating the reliability of the developed FEA model. The study found that fatigue life is most sensitive to changes in blade length, followed by width and then thickness, in this order. Analytical life cycles and Fe-Safe software show a percentage difference of less than 4.86%. This concludes that the numerical methodology developed can be used for real-life mistuned steam turbine blades subjected to variations in blade geometry.